Various types of ice level detecting devices are known in the art to detect a full ice level state of ice in an ice bin. Many of these devices use mechanical arms, photo sensors, ultrasonic energy and thermostats.
U.S. Pat. No. 3,911,691 to Kohl et al. teaches an ice level sensing mechanism that includes a generally vertically disposed pendulum element that is pivotally supported at an upper end. The lower end of the pendulum is moveable in any direction. The ice level sensing mechanism also includes a contact device that is disposed in a surrounding relationship to a portion of the pendulum element. The contact device is engaged by the pendulum element when the ice level within the ice storage bin reaches a predetermined magnitude. The pendulum and the contact device are operatively connected to an electrical control circuit associated with an ancillary ice producing machine that supplies ice to the storage bin.
U.S. Pat. No. 4,662,182 to Tsukiyama et al. discloses an ice storage detector for use with an ice maker and ice reservoir. The ice storage detector includes an ice detection plate that is pivotally mounted in the ice reservoir. The ice storage detector also includes means for supporting the detection plate and a proximity sensor that is disposed above the detection plate. The detection plate is pivotable about a horizontal shaft between a non-ice detecting position and an ice detecting position. In the ice detecting position, the ice detection plate is displaced in a direction away from a top of the ice pile to cause the proximity sensor to generate an ice detecting signal.
U.S. Pat. No. 4,822,996 to Lind reveals an ice bin level sensor with a time delay. The ice bin level sensor includes an electrical circuit that operates an ice maker using a light interrupter system. A pulsed light source is positioned for interference when the ice has reached a predetermined level in the ice containing bin. The circuit activates the ice maker once the light source is sensed for a predetermined period of time and deactivates the ice maker when the light source is not sensed for another predetermined period of time.
U.S. Pat. No. 4,947,652 to Arcangeli teaches an ice level control for a flake ice maker. The flake ice maker has a housing, a refrigerated surface in the housing, a rotary scraper for scraping ice from the refrigerated surface and for discharging the scraped ice into an underlying ice bin. The rotary scraper is driven by a rotary drive shaft electrically grounded to a common ground with a control circuit connected for controlling rotation of the scraper. A sensing arm is attached to the drive shaft for sweeping a path in the ice bin. A switch actuatable upon contact of the arm with accumulated ice in the ice bin completes an electrical circuit through the drive shaft thereby interrupting the operation of the ice maker.
U.S. Pat. No. 5,060,484 to Bush et al. discloses a bin level control circuit and a transducer mounting system for an ice making machine. An ultrasonic bin level control circuit employs a fail-safe circuit to shut off a compressor when echoes are late or absent. A transducer mounting system facilitates installation and removal of a transducer for servicing and cleaning. A level detector compares a reference signal with a reflected signal with the ice reaching a desired level when the reflected signal overlaps the reference signal. When the desired level is reached, the reference signal is modified through feedback to prevent short cycling of the compressor.
U.S. Pat. No. 5,131,234 to Furukawa et al. teaches an ice level detecting apparatus for ice making machines. The ice detecting apparatus includes a thermostat having a temperature sensor element and a holder for holding the sensor element in a spaced relationship with an ice stocker inner wall.
Ice level detector devices that use moveable mechanical arms, pendulums or levers can be problematic. Particularly, the moveable mechanical arms, pendulums and levers can break or become "jammed," sometimes as a result of ice build-up. Further, moveable mechanical levers, pendulums and arms are relatively sensitive to rugged handling. The photosensitive or ultrasonic ice level detectors can also be problematic. Particularly, the photo sensors or ultrasonic transducers can be rendered inoperative because of mold, condensation, scale or algae build-up thereon. As a result, these devices must be kept clean. Also, such devices are not conducive to rugged handling. Although an ice level detector device using a thermostat can be effective, the thermostat is also not conducive to rugged handling.